In manufacturing electronic devices such as semiconductor devices, a plasma processing apparatus is used for processes such as etching and film formation. A capacitively-coupled plasma processing apparatus is known as one type of plasma processing apparatus. The capacitively-coupled plasma processing apparatus generally includes a chamber body, an upper electrode, and a lower electrode. The upper electrode and the lower electrode are disposed such that a space within a chamber provided by the chamber body is defined therebetween. In this plasma processing apparatus, a gas is supplied to the chamber to form a high frequency electric field between the upper electrode and the lower electrode. The gas is excited by the high frequency electric field to generate plasma. A workpiece is processed by ions and/or radicals generated from the plasma.
In the related art, a plasma processing apparatus configured to form a high frequency electric field within a plurality of chambers using a single high frequency power supply is known as one type of the capacitively-coupled plasma processing apparatus. Such a plasma processing apparatus includes a plurality of upper electrodes, a plurality of lower electrodes, a primary coil, and a plurality of secondary coils. The plurality of upper electrodes is respectively installed in upper spaces within the plurality of chambers, and the plurality of lower electrodes is respectively installed in lower spaces within the plurality of chambers. A high frequency power supply is connected to the primary coil. The primary coil and the plurality of secondary coils are electronically coupled to each other. One end of the plurality of secondary coils is respectively connected to the plurality of upper electrodes. The other ends of the plurality of secondary coils are respectively connected to the plurality of lower electrodes. A plurality of variable condensers is respectively connected between the other ends of the plurality of secondary coils and the plurality of lower electrodes. These variable condensers are installed to reduce impedance of a closed circuit including the plurality of secondary coils.
In this type of plasma processing apparatus, i.e., the plasma processing apparatus configured to form a high frequency electric field within the plurality of chambers using a single high frequency power supply, it is required to enhance the efficiency of power supply to the electrodes for the plurality of chambers.